In order to manufacture compact cellular phones with attractive designs, folding cellular phones have been developed.
FIG. 1 is a diagram showing an example of the construction of a conventional folding cellular phone. Referring to FIG. 1, the cellular phone comprises an upper housing 100, a lower housing 200 and a hinge 300. The upper housing 100 includes an earpiece or speaker, while the lower housing 200 includes a mouthpiece or microphone. The hinge 300 connects the upper and lower housings 100 and 200. The upper and lower housings 100 and 200 are mutually rotated about the hinge 300 as a rotation axis to fold the cellular phone.
The upper and lower housings 100 and 200 are provided at their one edges with hinge semi-cylindrical portions 301 and 302, respectively, as part of the hinge 300. The hinge semi-cylindrical portions 301 and 302 extend along about half the interior circumferential surface area of the hinge 300 with a radius approximately equal to that of the hinge 300.
Both the hinge semi-cylindrical portions 301 and 302 present a substantially hollow cylindrical appearance when the cellular phone is unfolded. That is, when the upper and lower housings 100 and 200 are in their open or spread positions, the semi-cylindrical hollows of the hinge semi-cylindrical portions 301 and 302 are arranged adjacent to each other on the same axis to form one hollow part in the hinge 300. In Japanese Patent No. 2821333, there is described in detail of the aforementioned construction of the hinge.
In the process of manufacturing the cellular phone, circuit boards are mounted on the upper and lower housings 100 and 200. FIG. 2 is a diagram showing the upper and lower housings 100 and 200 in their open positions and circuit boards to be mounted thereon. As can be seen in FIG. 2, a circuit board 401 is mounted on the upper housing 100, and a circuit board 402 is mounted on the lower housing 200. Mounted on the circuit boards 401 and 402 are integrated circuits each consisting of the integration of electronic components that implement the call transmission/reception function of the cellular phone. The circuit boards 401 and 402 are electrically connected via a flexible cable 403. As shown in FIG. 2, the flexible cable 403 is wound or twisted in a spiral with one turn, and flexible to the extent that no disconnection of wiring occurs even if it is bent to some degree.
FIG. 3 is a diagram showing the upper and lower housings 100 and 200 after the circuit boards 401 and 402 are mounted thereon. The cellular phone can be assembled by simply placing the circuit boards 401 and 402 on the upper and lower housings 100 and 200. This simple operation achieves high efficiency in the assembly process. In the process of mounting the circuit boards 401 and 402 on the upper and lower housings 100 and 200, the flexible cable 403 is accommodated in the hollow part formed of the hinge semi-cylindrical portions 301 and 302. Thereby, when the cellular phone as a completed product is folded and unfolded, the relative position of the flexible cable 403 does not change because of its flexibility, and also no disconnection of wiring occurs. The hinge 300 has the construction as described above, not only to place emphasis on factors such as miniaturization and design, but also to reserve the hollow part for accommodating the flexible cable 403 as well as to achieve high operating efficiency in the assembly process.
In order to ensure high operating efficiency, the assembly process necessarily requires such simple operation as just placing the circuit boards 401 and 402, which are electrically connected via the flexible cable 403, on the upper and lower housings 100 and 200. The hollow part formed of the hinge semi-cylindrical portions 301 and 302 arranged adjacent to each other on the same axis is essential for the operation.
FIG. 4 is another diagram showing another example of the construction of a conventional folding cellular phone. Referring to FIG. 4, the cellular phone comprises an upper housing 100, a lower housing 200 and a hinge 300. The upper housing 100 includes an earpiece or speaker, while the lower housing 200 includes a mouthpiece or microphone. The hinge 300 connects the upper and lower housings 100 and 200.
Similarly to those of FIG. 1, the upper and lower housings 100 and 200 are provided at their one edges with hinge semi-cylindrical portions 301 and 302, respectively. When the upper and lower housings 100 and 200 are in their open positions, the semi-cylindrical hollows of the hinge semi-cylindrical portions 301 and 302 are arranged adjacent to each other on the same axis to form one hollow part, in which a flexible cable is accommodated.
Besides, differently from those of FIG. 1, the edge of the lower housing 200 is arranged vertically above the edge of the upper housing 100. By virtue of this construction, the cellular phone as a completed product has a unique and creative design. In addition, the size of the cellular phone is reduced by the overlap of the upper and lower housings 100 and 200. Thus, further miniaturization can be achieved. On the other hand, it seems that the thickness of the cellular phone is increased by the overlap. In this regard, however, there is no problem if the cellular phone is so designed, for example, that the thickness of each housing is reduced, or the thickness of a rear cover attached to each housing is reduced.
As an advantage of the above construction, it may be cited that a certain degree of space is reserved, as compared to the cellular phone shown in FIG. 1, at the edge of the lower housing 200 on the side where the hinge 300 is formed. That is, it is possible to reserve an area around the hollow part. Thus, an additional component, especially a large and thick component, can be mounted on the area, which expands the freedom of the design of the cellular phone.
However, in the assembly process, the construction shown in FIG. 4 does not allow circuit boards to be simply placed on the upper and lower housings 100 and 200 in their open positions. This is because the part at the edge of the lower housing 200 indicated by white arrow “A” interferes with the process of accommodating the flexible cable in the hollow part formed of the hinge semi-cylindrical portions 301 and 302.
If the assembly process is altered to avoid the interference, the operating efficiency is reduced. More specifically, if one end of the flexible cable is threaded through an aperture at the edge of the lower housing 200 indicated by white arrow “A”, and then connected to the circuit boards, the efficiency of the assembly process decreases compared to the case where the circuit boards, which have already been connected to the flexible cable, are simply placed on both the lower housings 100 and 200.
One approach to avoiding the decrease in the operating efficiency involves cutting off the edge of the lower housing 200 indicated by white arrow “A”. However, in the case of the cellular phone assembled in the above manner into a completed product, the flexible cable that is supposed to be accommodated inside the phone is exposed at the edge of the lower housing 200 cut off during the assembly process. The exposure of the flexible cable detracts from the design and appearance of the cellular phone.